多项选择题
Which two protocols are used by bridges and/or switches to prevent loops in a layer 2 network?（）
A.802.1d B.VTP C.802.1q D.STP E.SAP
多项选择题 Which two link protocols are used to carry multiple VLANs over a single link?（）
多项选择题 Which two benefits are provided by creating VLANs?（）
多项选择题 Which two benefits are provided by using a hierarchical addressing network addressing scheme?（）
